Since fullerene (Buckminster fullerene C60), a soccer ball shaped molecule consisting of 60 carbon atoms, was discovered by H. W. Kroto, R. E. Smallry, and R. F. Curl in 1985, and a carbon nanotube, a tube formed of a rolled graphene sheet (a hexagonal carbon network plane) was discovered by Iijima in 1991, methods of producing the so-called carbonaceous particles including fullerene and carbon nanotubes, have been developed, and applications of the carbonaceous particles to various fields are being investigated.
Methods proposed of producing a fullerene include: the oven laser-vaporization method for extracting a fullerene from soot obtained by irradiating graphite with a laser in an argon gas flow heated to a high temperature of about 1,200° C.; the resistive heating method for extracting a fullerene from soot obtained by ohmic-heating a graphite rod in a helium gas; the arc discharge method for extracting a fullerene from carbon soot obtained by generating an arc discharge between two graphite electrodes; the high frequency induction heating method for extracting a fullerene from soot obtained by heating and evaporating raw graphite by passing of a spiral current generated by high-frequency induction therethrough; the combustion method for extracting a fullerene from soot obtained by combusting a mixed gas of benzene and oxygen diluted with an argon gas, and the like. In addition, in Japanese Patent Application Laid-Open No. H5-186865, a method is disclosed which produces a carbon cluster by arc-discharging or resistive-heating of a pair of electrodes consisting of a carbon rod and a metal rod and arranged in a vessel filled with an inert gas. Moreover, in Japanese Patent Application Laid-Open Nos. H6-56414 and 6-32606, a production method is disclosed which separates a fullerene from a solid matter obtained by supplying an aromatic compound into a generated thermal plasma.
Because a carbon nanotube has an electron emission function, a hydrogen occlusion function, and further a function of effectively storing/releasing lithium through an electrochemical reaction, its applications to an FED (Field Emission display), a lithium secondary battery, or a hydrogen occlusion system are studied.
Methods proposed of producing a carbon nanotube include: the arc discharge method for conducting an arc discharge in a gas atmosphere containing a carbonaceous raw material such as a hydrocarbon; the laser vaporization method for forming a carbon nanotube by irradiating graphite as a target with a laser to vaporize it; the thermal decomposition method for thermally decomposing a gas of acetylene or the like as a carbonaceous raw material on a substrate on which a catalyst of cobalt metal or nickel metal is arranged.
In addition, in Japanese Patent Application Laid-Open No. H6-157016, a method is disclosed which generates an arc discharge between a pair of carbon rods by application of a DC current in a He gas atmosphere to deposit a carbon nanotube on a cathodic carbon rod. In Japanese Patent Application Laid-Open No. H9-188509, a method is disclosed which produces a carbon nanotube by generating an electrodeless high-frequency plasma and supplying a carbonaceous raw material and a metallic catalyst into the plasma. In Japanese Patent Application Laid-Open No. H10-273308, a method of producing a carbon nanotube by a laser vaporization method of irradiating a carbon rod with a laser, is disclosed. In Japanese Patent Application Laid-Open No. 2000-86217, a method of producing a carbon nanotube is disclosed which decomposes a hydrocarbon at a high temperature on a catalyst consisting of metallic molybdenum or a metallic-molybdenum-containing compound to deposit a carbon nanotube on the catalyst. In Japanese Patent Application Laid-Open No. 2000-95509, a method is disclosed which provides a tip of a rod-like anode containing carbon and a non-magnetic transition metal element and a tip of a rod-like cathode in opposition to each other, generating an arc discharge therebetween to generate a vapor of carbon and fine particles of the non-magnetic transition metal element, thereby depositing a carbon nanotube at a base end of the cathode.
However, the above-mentioned prior art methods of producing a carbonaceous particle such as a fullerene and a carbon nanotube, provide carbonaceous particles of a low purity, have problems in a production apparatus and a purification process, and consequently it is difficult for the methods to manufacture carbonaceous particles of a high purity in large quantities at a low cost.